1. Field of the Invention
This invention relates to a semiconductor device wherein a bipolar transistor and a junction type field effect transistor are formed on a common substrate.
2. Description of the Prior Art
A bipolar transistor for signal processing results in a a high speed operation in order to obtain a lower power consumption and a high frequency for a system which employs the bipolar transistor.
In particular, a pattern of a bipolar transistor is made finer to reduce the parasitic capacity of the bipolar transistor to realize operation with a low current while an epitaxial layer is formed in a thin film to allow a high frequency. Such bipolar transistors for signal processing highly are integrated into a single chip device.
A high voltage resisting external element of the high voltage driven type is known. For example, a high voltage resisting transistor for use with a variable capacitance diode of a tuner or the like is, when it is to be used in order to prevent possible deterioration in the characteristics of the tuner and together with a bipolar transistor for signal processing, externally connected to the bipolar transistor for signal processing.
However, when both a high voltage resisting transistor and a bipolar transistor for signal processing are to be used, if the high voltage resisting transistor is externally connected to the bipolar transistor for signal processing, then reduction in the number of externally connected parts is not achieved. Further, a great number of parts are required, and a step for externally connecting the high voltage resistance transistor to the bipolar transistor for signal processing is required, which results in high production costs.